The following section is presented for informational purposes only. The inclusion of material in this section should not be considered to be an admission that such material is prior art to the present application.
Some embodiments disclosed herein are directed to systems, devices, and methods for seismic sensing, e.g., suitable for use as a geophone. A geophone is a device that converts ground movement (displacement, velocity, or acceleration) into an electrical signal (e.g., a voltage) that may be recorded, e.g., at a recording station or in on board memory in a sensor package. The deviation of this measured voltage from the base line is called the seismic response and is analyzed to determine the underground structure of the earth.
Geophones may be passive analog devices that include, e.g., a spring-mounted magnetic mass moving within a wire coil to generate an electrical signal. Some geophones may be based on microelectromechanical systems (MEMS) technology which generates an electrical response to ground motion through an active feedback circuit to maintain the position of a small piece of silicon.
The response of a coil/magnet geophone may be proportional to ground velocity, while MEMS devices may respond proportional to acceleration. MEMS devices may have a higher noise level than coil/magnet geophones and thus may be limited to use in strong motion or active seismic applications.
Geophones may be used in reflection seismology to record the energy waves reflected by the subsurface geology, e.g., for the purpose of locating subsurface oil or gas deposits.